1. Field of the Invention
The present invention relates generally to treatment of water, and more particularly to treatment of waste water utilizing a plurality of adjacent conduit members positioned to receive an air flow or gas flow therethrough to lift and circulate the water to be treated. Preferably, the gas utilized is air or oxygen and provides for aerobic biological treatment of the water. Optionally, particles may be added to the solution to increase the surface area carrying the desirable biota.
2. Description of the Related Art
An early process utilized to purify or treat water such as waste water was the Trickling Filter Process. Initially, this aerobic biological process involved trickling the water to be treated over a bed of rocks. The process evolved to the use of plastic to provide a receptive, enlarged surface area for the biota. Accordingly, greater surface area could be provided in a given volume and the reduction in weight enabled towers as high as forty feet to be employed. The process was further improved by recycling a portion of the effluent back over the biota. However, while the biota cultivated on the plastic surface is efficient and effective in removing contaminants, energy requirements to pump the water and a desirable recycle stream to such heights are substantial.
The Activated Sludge Process was developed after the Trickling Filter Process to provide for more thorough treatment of waste water contaminants and facilitate treatment of large quantities of waste water. Like the Trickling Filter Process the Activated Sludge Process is an aerobic biological process and depends upon providing substantial amounts of oxygen to the micro-organisms comprising the biota. Rapid mixing is essential to contact the micro-organisms with the contaminant which serves as nourishment for the micro-organisms. A clarifier is required in the Activated Sludge Process. Basically, a clarifier provides a quiescent volume which allows the activated sludge in the form of colonies of micro-organisms to settle and thus be conveniently available for removal from the clarifier. Clarified water is removed from another zone of the clarifier. A recent improvement to the Activated Sludge Process involves the addition of activated carbon particles to the reactor. The activated carbon absorbs the contaminants and thus provides a greater resident time for the micro-organisms to consume the contaminants as nourishment.
Rotating biological films or discs were developed as an improvement over the Trickling Filter Process in order to treat large flows and avoid the prohibitive energy demands required to pump waste water to the top of high towers. Typically, large discs rotate at a rate of about 1 to 5 rpm to enable biota to build up on the surface of the disc. Since the disc is partially in the water and partially in the atmosphere, oxygen is supplied to the biota as the disc rotates out of the water to the surrounding atmosphere. Nourishment, in the form of contaminants in the waste water, is provided to the biota as the disc carrying the biota rotates through the waste water. However, the process is limited by the relatively low rate at which the disc can be rotated. Biota colonies carried on the disc are rather fragile and will not withstand substantial disturbance resulting from the discs moving through the waste water in conjunction with centrifugal force resulting from even moderate rotational speeds.
Thus the prior art generally relates to processes which are effective but relatively slow and/or energy intensive in treating water. Accordingly, an advantage of the instant invention is a compact, efficient biological reactor which is effective and efficient in reducing the contaminants in water.
Another advantage of the instant invention is the efficiency resulting from the use of gas to aerate and circulate the waste water over a compact volume having great surface area to support biota growth.
Yet another advantage of the instant invention is the vigorous mixing and aeration of the water to be treated thereby providing oxygen and nourishment in the form of contaminants to the biota growth on the biological reactor.
These and other advantages of the instant invention will become apparent from the following description.